Thermoelectric power generator

ABSTRACT

The purpose of the invention is to provide a thermoelectric power generation body capable of generating power not only from solar heat and geothermal heat but also from a heat source of medium or low temperature which has been impossible to be utilized by the conventional art, with high thermal efficiency.  
     The thermoelectric power generation body of the present invention is composed of a solid layer of fine particles of sulfide semiconductor having a relatively small band gap coagulated in a state moist with water, a solidified redox reaction system adjoining to the one plane of the solid layer and generating lower reaction potential on the vacuum basis and an anode adjoining to the outer side of the system, and a cathode adjoining to the opposite plane of the solid layer and generating higher reaction potential in a equilibrating reaction state.  
     The reaction potential difference liberate the thermally excited carriers between bands, further gives energy for violating the equilibrium to enable the carriers to do work against the outside.  
     As the solidified redox reaction system has no fluidity, the corrosion of cathode does not occur, which contribute to the compactness of the construction, persistency of output, and easiness of maintenance of the thermoelectric power generation body.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a thermoelectric powergeneration body and more particularly to a thermoelectric powergeneration body capable of generating power not only from solar heat andgeothermal heat but also from a heat source of medium or low temperaturewhich has been impossible to be utilized by conventional arts, with highefficiency of thermoelectric conversion.

[0003] 2. Description of the Related Art

[0004] At the present time, heat energy is converted into electric powermainly by a heat engine in which the process is: heat energy→highpressure steam→turbine→generator→electric power.

[0005] This method of converting heat energy into electric power havegreatly contributed as power sources for supporting people's life insociety, but there is a problem that it accompanies a large waste heatwith its thermal efficiency of 45% at the best.

[0006] To combine a gas turbine to this method has already beenattempted to good purpose, and it is applicable to thermal powergeneration using fossil fuels but not applicable to nuclear powergeneration.

[0007] Power generation by fuel cells seems like a promising one from apoint of view of largely improving thermal efficiency, at present theusable fuel is limited to hydrogen which is comparatively expensive andthere still remain problems.

[0008] On the other hand, the conversion of heat energy into electricpower using devices based on Seebeck effect is already established, butits thermal efficiency is 20% at the best and not in the state ofgeneral use on a large scale.

[0009] Electric power will continue without doubt to be necessary as animportant energy to support people's life in society in the future. Arequisite for the process of obtaining electric power from heat energyis to attain thermal efficiency as high as possible now that globalenvironment crisis is strongly acknowledged.

[0010] However, there is a theoretical upper limit which can not beexceeded in thermal efficiency of each process of converting heat energyinto electric power, and in any of the processes its thermal efficiencyhas reached near the upper limit by continued effort. Therefore, a leapin the concept of the method of thermoelectric conversion itself isnecessary to get a quantum leap in thermal efficiency.

[0011] The inventors have investigated the operating mechanism ofalready-existing solar cells and devices utilizing Seebeck effect andworked toward development of a thermoelectric conversion device whichoperates at room temperature and moreover without large temperaturedifference in the device.

[0012] Two inventions made heretofore were applied for patent; the firstone is disclosed Japanese Unexamined Patent Publication 6-151978 and thesecond is disclosed Japanese Unexamined Patent Publication 8-306964.

SUMMARY OF THE INVENTION

[0013] Here, the idea and invention obtained through a series of studiesmade previously will be described, in which mention will also be made ofthe signification of the present invention.

[0014] The basic configuration of the thermoelectric power generationbody according to the present invention is as follows:

[0015] Basic operation is as follows:

[0016] 1) Electrons are thermally excited in between energy bands in thesemiconductor.

[0017] 2) When appropriate electric field exists in the semiconductor, athe thermally excited electrons gather in region (C) of conduction bandand on the other hand positive holes gather in the region (A) of valenceband. This is charge separation by the internal electric field.

[0018] 3) However, in the state cited above, the electrons and positiveholes are in the state of thermal equilibrium with Fermi level of region(A) coinciding with that of region (C).

[0019] 4) If Fermi level of region (C) can be raised to a higher levelthan that of region (A) by use of some means, the electrons gathering inthe region (C) get energy to violate the thermal equilibrium state andflow through the circuit with load as electric current whileaccomplishing work against external load and arrive at region (A) wherethe electrons meet with the positive holes, then again thermally excitedin between the bands and return to region (C) of conduction band, thusthe current flow continues.

[0020] The heat energy used for thermal excitation in between the bandsis converted into electric power by this process. A temperaturedifference between both poles is not necessary, which is different fromthe case of Seebeck effect. Therefore, as the heat energy flowed intothe body does not flow out to anywhere but converted into electricpower, thermal efficiency would be 100%. This is the idea ofthermoelectric conversion that occurred to the inventors. The inventorshave made repeated studies to realize the idea, and made several keyinventions cited below.

[0021] The band gap of semiconductor is desirable to be equal or under 1eV in order to induce the thermal excitation of electrons in between thebands at room temperature or a little higher temperature, which is wellknown. The condition for establishing an appropriate internal electricfield to separate the carriers excited in between the bands is alsopublicly known. That is, in the configuration of an device shown below,

[0022] the condition for establishing appropriate internal electricfield to gather positive holes to region (A) of valence band andelectrons to region (C) of conduction band is:

[0023] with n-type semiconductor;

Δφ_(A)=φ_(AN)−φ_(n)≧(Eg−0.2)/q  [1]

Δφ_(C)=φ_(n)−φ_(CA)≧0  [2]

[0024] with p-type semiconductor;

Δφ_(A)=φ_(AN)−φ_(p)≧0  [3]

Δφ_(C)=φ_(p)−φ_(CA)≧(Eg−0.2)/q  [4]

[0025] where symbols denote φ work function (v) Eg band gap (eV) qcharge of an electron A position (A) C position (C) n n-typesemiconductor p p-type semiconductor AN anode CA cathode.

[0026] The first idea the inventors hit upon as a means to establishFermi level difference between region (A) and (C) is to increase minorcarrier density in the plane of a semiconductor violating the thermalequilibrium state by external action.

[0027] The configuration of an device the inventors proposed as a meansfor realizing the idea mentioned above is that, tellurium (Te) is usedas a semiconductor, copper (Cu) as an anode, aluminum (Al) as a cathode,The anode and cathode each is brought into close contact with the solidtellurium, and further glycerol is contacted to the cathode side.Properties of matter are as follows: Te: type of conduction ; p-type Eg; 0.32 eV φ: Cu ; 4.86 V Te ; 4.70 V Al ; 4.25 V.

[0028] These values of properties suffice the required conditions [3]and [4]. Further, electrons are separated due to the reaction of Alhaving high reactivity with glycerol and the electrons are implantedinto tellurium (Te) at the cathode.

[0029] According to the idea of the inventors, the electrons, which areminor carriers in tellurium (Te), externally implanted with highpotential level exceed the equilibrium state in both energy level anddensity, and would raise the Fermi level in region (C). The idea wasverified by the experiments and the inventors disclosed it in JapaneseUnexamined Patent Publication 6-151978. Though the invention enabled thedevice thermoelectric conversion, further increase of output wasrequired.

[0030] Further, crystalline semiconductor such as tellurium is notsuitable for producing a sheet-like semiconductor of large area.Producing a semiconductor in a sheet of large area is necessary for massproduction of thermoelectric power generation body, and a semiconductorsuitable for this object should be selected.

[0031] The inventors hit upon an idea of using sulfide semiconductor.This is based on the characteristic that sulfide semiconductor is ofionic bonding and a semiconductor which functions well can be obtainedby a comparatively easy production method. An idea of producing a sheetof large area utilizing the characteristic is that the fine particles ofsulfide semiconductor obtained by liquid phase reaction at normaltemperature shaped into a solid matter and hardened using an appropriatecarrier material and binder.

[0032] It is necessary that the sulfide semiconductor is in the statecontaining water moderately, and the fact that it contains waterachieves an important role as mentioned later. The electron affinity xof sulfide semiconductor was assumed to be 3.6˜3.8 V, and further thefollowing materials and the like which were semiconductors having bandgap Eg of equal or smaller than 1 eV were selected as constructionelements of the device:

Cu₂S(p-type, assumed Eg=0.6 eV)

FeS (n-type, assumed Eg=0.7 eV)

[0033] The output of the device mentioned before using tellurium assemiconductor is small because of small difference of Fermi levelbetween region (A) and (C). It was recognized that this is theconstraint which the method of making the density of minor carriershigher than that of the thermal equilibrium state has.

[0034] Thus, an idea occurred to the inventors was: electrochemicalreaction having low reaction potential on vacuum basis is allowed toexist steadily in region (A); on the other hand electrochemical reactionhaving high reaction potential on vacuum basis is allowed to existsteadily in region (C); the difference of both reaction potentials isapplied to the semiconductor as forward bias voltage; and a largedifference in Fermi level is established between region (A) and (C).

[0035] Here exist two preconditions. The first is that the reactionpotential generated in region (A) and that generated in region (C)should be linked. To realize the linkage, the semiconductor layerexisting between region (A) and (C) is required to be in the state ofcontaining water. A semiconductor containing water is attained only bythe method, as mentioned above, in which fine particles of semiconductorare reduced to a solid body while containing water. A crystallinesemiconductor can not address this requirement.

[0036] The second is that excessive diode current should not flow in thestate the forward bias is applied. This is attained by allowingsufficiently high schottkey barrier to exist in region (A), or allowingpotential barrier due to p-n junction to exist in the central regionbetween region (A) and (C).

[0037] In the thermoelectric power generation body prepared by thismethod, the potential barrier existing internally for separating thethermally exited carriers between bands contributes advantageously torestrain the diode current.

[0038] The inventors began by selecting a redox reaction system composedof a water solution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)_(2+n)(n=0, 1, 2)}.

[0039] The reaction potential of this reaction group exists in thefavorable region as follows:

E ⁰=0.06 V vs NHE (Hydrogen electrode potential basis)

[0040] (where n=2)

ψ_(A)=−4.49V vs Vacuum

[0041] Further, the reaction system has charge transport ability as acharacteristic of redox reaction, which is also a preferable feature.

[0042] Then, the inventors thought of allowing the following reactionsystem to exist in the equilibrium as a reaction to be allowed tosteadily exist in region (C) by using as cathode a metal having strongaffinity with S²⁻ which is an anion constituting the semiconductor:

Cathode material+S²⁻←→Sulfide+2e ⁻

[0043] It is in the state the liberated electrons by the reaction aretaken away that the reaction proceeds rightward in the above reaction,so the equilibrium can be kept if isolated existence of electrondemanding reaction center is not allowed to exist in the reactionsystem. Although a redox reaction system includes electron demandingreaction, electrons are not completely absorbed substantially orirreversibly as long as the balance is sustained between reductionreaction and oxidation reaction.

[0044] The reaction potential difference obtained by linkingelectrochemical reaction in region (A) and that in region (C) issufficiently large as shown in Table 1. TABLE 1 Cathode material E⁰ (Vvs NHE) ψ_(c) (V vs Vac.) Δ ψ = ψ_(c) − ψ_(A) (V) Cu −0.89 −3.54 0.95 Fe−0.965 −3.47 1.02

[0045] To provide a redox reaction system to an anode side is well knownin the art of wet-type solar cell. However, the finding that Fermi leveldifference is established by allowing reaction potential due toelectrochemical reaction to exist at both the anode side and the cathodeside and the application of the difference of the both reactionpotentials to a semiconductor layer as a forward bias voltage is a newone obtained by the inventors, by which new ground of utilizing thethermal excitation phenomenon for a thermoelectric conversion wasbroken. The inventors have applied for patent with a series of theinventions mentioned above as disclosed in Japanese Unexamined PatentPublication 8-306964.

[0046] However, there remained a problem that the corrosion of cathodematerial should be deterred in the method according to JapaneseUnexamined Patent Publication 8-306964. The corrosion is caused by thefact that the redox reaction liquid existing in the anode region osmosesgradually into the semiconductor layer and intrudes into the cathoderegion where it reacts with the cathode material. As a natural result,the damage of cathode deteriorates the durability of the device.

[0047] To cope with this problem, the inventors tried at first to lowerthe permeability of the semiconductor layer as low as possible but didnot succeed in sufficing at the same time two mutually contradictoryrequirement, i.e. to link the reaction potentials generated at the bothplanes of the semiconductor layer and to decrease the permeability ofthe layer.

[0048] As a next approach, the inventors hit upon an idea in that thewater solution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)_(2+n)(n=0, 1, 2)} is occluded ina suitable adsorbent, a necessary amount of binder is added, and furthera sufficient amount of ammonium salt is added for the reason mentionedlater to solidify and harden the reaction liquid for depriving it offluidity in order that no reaction liquid may intrude into the cathoderange.

[0049] The inventors found that activated carbon shows an extremelysuperior performance among a variety of existent adsorbent and succeededin solidifying redox reaction liquid.

[0050] Further, the electrolytic water solution room was eliminated fromthe cathode region in correspondence with the solidification of theanode reaction liquid, because if electrolytic water solution remains inthe cathode range the liquid intrudes into the anode region to allow theelution of the redox reaction system solidified resulting in the loss ofeffect of the solidification.

[0051] The inventors thus succeeded in generating large output incontinuation by the thermoelectric power generation body in which asolidified redox reaction system is provided in the region of an anodeand further the region of a cathode is reduced to the semi-dried statewhere the cathode contacts a semiconductor. Moreover, this solid stateconstruction is simple, free of trouble such as leakage of liquid, andsuitable for commercialization. The invention cited above is theskeleton of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

[0052]FIG. 1 is a schematic representation showing the structure of adevice with the solidified redox reaction system exposed to theatmosphere in the first embodiment.

[0053]FIG. 2 is a conceptual rendering for explaining the transfer ofelectrons and the change of potential in a device according to thepresent invention.

[0054]FIG. 3 is a schematic representation showing the configuration ofthe device in the second embodiment.

[0055]FIG. 4 is a schematic representation showing the configuration ofthe device in the third embodiment.

[0056]FIG. 5 is a schematic representation showing the construction of adevice of the first comparative example in which the redox reactionsystem is liquid phase and cathodes are spider coils immersed inglycerol.

[0057]FIG. 6 is a schematic representation showing the structure of adevice of the second and third comparative examples with the solidifiedredox reaction system isolated from the atmosphere. Reference numbers inthe drawings denote: 11 is an anode(corrugated thin plate of platinum),12 is a jig for holding the anode, 13 is a solidified redox reactionsystem, 14 is a sulfide semiconductor, 15 is a cathode(thin plate ofpure iron), 21 is an anode(thin plate of platinum), 23 is a solidifiedredox reaction system, 24 is a sulfide semiconductor, 25 is acathode(thin plate of pure iron), 1 is a circuit with load, 0 is asupplementary circuit, R₁ is a resistance of load, R₀ is a resistancefor adjustment, E₀ is a supplementary power source, 31 is an anode(thinplate of graphite), 33 is a liquid state redox reaction system, 34 is asulfide semiconductor and 35 is a cathode(spider coil-like thin wireimmersed in glycerol).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0058] The action in a device of the present invention will be explainedhereinbelow. As mentioned before, water solution of {Cu⁺ (NH₃)₂˜Cu²⁺(NH₃)_(2+n)(n=0, 1, 2)} has two roles to perform as redox reactionsystem, that is, to generate reaction potential and to transfer electriccharge.

[0059] Among them, the charge transfer is expected to be performed bythe diffusion of cations in the form of Cu⁺(NH₃)₂ and Cu²⁺(NH₃)_(2+n) inthe water solution, and it is supposed that the charge transfer abilityis lost in the state the cations are fixed on the adsorbent and as aresult reaction potential generation ability is also lost, butwonderfully, in the actual system using activated carbon as adsorbent,the charge transfer ability increased on the contrary and reactionpotential generation ability was also raised.

[0060] The next thing the inventors learned was that the solid bodywhich consists of activated carbon powder adsorbing and holding theredox reaction liquid and is hardened using burnt gypsum as bindermaintains a steady reaction state only when it receives the action ofoxygen. When the action of oxygen can not be experienced, electricconduction ability of the redox reaction system decreases with time, andthe output of the thermoelectric power generation body decays. It wasrecognized that such need of oxygen is not a peculiar problem to asolidified redox reaction system, it is also a problem to the watersolution and is a phenomenon intrinsic to the redox reaction system of{Cu⁺(NH₃)₂˜Cu²⁺(NH₃)_(2+n)(n=0, 1, 2)}.

[0061] To maintain a steady state in the redox reaction system, it isnecessary that both densities of reduction type cations Cu⁺ (NH₃)₂ andoxidation type cations Cu²⁺ (NH₃)_(2+n) are in a steady state.

[0062] Oxidation reaction is:

Cu⁺(NH₃)₂ +nNH₃→Cu²⁺(NH₃)_(2+n) +e ⁻

[0063] Reduction type reaction is:

Cu²⁺(NH₃)_(2+n) 30 e ⁻→Cu⁺(NH₃)₂ +nNH₃

[0064] In the state either of the reactions proceeds dominantly, therearises inevitably uneven mass distribution of reaction matter and thesteadiness of reaction will be lost. Here the inventors focusedattention on the point that the occurrence of the reaction is influencedby the value of n of an oxidation type cation Cu²⁺(NH₃)_(2+n),recognized the importance of maintaining high value of n, andinvestigated thoroughly the condition of realizing it to obtain newfindings.

[0065] Gibbs generation energy concerning the complex ion in the watersolution is obtained from the table of constant of properties asfollows: Cu^(+ (NH) ₃)₂ ΔG⁰ _(f298) =  −65.01 kJmol⁻¹ Cu^(2+ (NH) ₃)₂ −30.49 Cu^(2+ (NH) ₃)₃  −73.17 Cu^(2+ (NH) ₃)₄ −111.33

[0066] Calculation results of oxidation reaction potential of reactionCu⁺ (NH₃)₂+nNH₃→Cu²⁺ (NH₃)_(2+n)+e⁻ using above cited values are shownin Table 2. TABLE 2 n ΔG_(R.298) (kJ) E⁰ (V vs NHE) 0 33.77 0.350 117.66 0.183 2  6.06 0.063

[0067] It is recognized from this table that, reduction reactionproceeds dominantly over oxidation reaction when n is small and when n=2oxidation reaction becomes easy to occur balancing with reductionreaction. Therefore, it is necessary to keep n=2 in order to attain asteady state of reaction system. Essentially reaction Cu²⁺(NH₃)_(2+n)=Cu²⁺ (NH₃)₂+nNH₃ is an equilibrating reaction, and if thedensity of NH₃ in the vicinity of Cu²⁺ (NH₃)_(2+n) is sufficiently high,the state of n=2 is maintained. On the other hand, when the density ofNH₃ becomes lower than that of equilibrium state, the value of ndecreases resulting in uneven distribution of reduction type complex ionCu⁺ (NH₃)₂.

[0068] Oxygen takes on the task of reducing unevenly distributed Cu⁺(NH₃)₂ to Cu²⁺ (NH₃)_(2+n) by oxidation. The reaction is as follows:

[0069] If OH⁻ formed here is left to remain as it is, it intrudes intothe cathode region to corrode the cathode and moreover allows dielectrichydroxide to be formed on the electric conduction face of the cathode,which is unfavorable. Therefore, OH⁻ should be eliminated in the redoxreaction system. This is done by the reaction NH₄+OH⁻→NH₃+H₂O. So, it isnecessary to allow a sufficient amount of ammonium salt, i.e., ammoniumchloride or ammonium sulfate to coexist as reaction material beforehandin the redox reaction system. Advantageously, NH₃ formed like thiscontributes to maintaining high density of NH₃ in the vicinity of Cu²⁺(NH₃)₄.

[0070] As mentioned above, the action of oxygen is important, and theinventors thought up to open the anode room to the atmosphere and tosecure a large surface area of the redox reaction system in order tomake it easy for the system to receive the action of oxygen.

[0071] Thus, the steady maintenance of the density of Cu²⁺ (NH₃)₄ ismade possible in the solidified redox reaction system having a largesurface area for easy reception of action from the atmosphere, in whichthe water solution of {Cu⁺(NH₃)₂ Cu²⁺(NH₃)_(2+n)(n=0, 1, 2)} is carriedon activated carbon and ammonium salts is added. It is supposed that theactivated carbon acts as catalyst to help the action of oxygen andfurther as adsorbent to hold NH₃.

[0072] A thermoelectric power generation body provided with thesolidified redox reaction system according to the idea and inventiondescribed above generates output exceeding that of a thermoelectricpower generation body provided with a liquid state redox reaction systemwithout accompanying the damage of cathode due to corrosion. This willbe shown in comparison of the first, second, and third embodiments withthe first comparative example.

[0073] Although the problem of excessive OH⁻ can be solved as mentionedabove, the inventors cannot but pay attention to the fact that thereremained the problem that electron demanding action by the reaction ofH₂O+½O₂+2e⁻→2OH⁻ promotes electron liberation reaction at the cathodeand consumes the cathode due to the action of chemical cell.

[0074] Cathode reaction is as follows:

Fe+S²⁻→FeS+2e ⁻ E ⁰=−0.965V vs NHE  (1)

Fe→Fe²+2e ⁻ E ⁰=−0.440V vs NHE  (2)

[0075] Reaction (1) steadily exists in region (C), breaks theequilibrium of [FeS . . . S²⁻. . . Fe cathode] bearing the task ofgenerating high reaction potential and conducting electrons, andconsumes S²⁻ of finite amount. On the other hand, reaction (2) occursafter reaction (1) proceeds no longer, in which Fe²⁺ formed thereindeteriorates the electron conduction ability between FeS and Fe. Thesecondary reaction like this is of a kind which is accompanied due tothe existence of the process of substantially absorbing electrons in aredox reaction system.

[0076] Therefore, to allow only the reaction of H₂O+½O₂+2e⁻→2OH⁻ toachieve desired action and not to allow absorption of electrons in aredox reaction system has become the next challenge.

[0077] The inventors solved the problem through achieving a balancebetween giving and receiving of electrons in a redox reaction system byadding to the solidified redox reaction system an oxidation electrodewhich is energized by an auxiliary power source to allow the reaction of2OH⁻→H₂O+½O₂+2e⁻ to occur.

[0078] This will be explained in reference with an example of thethermoelectric power generation body according to the present inventionshown in FIG. 3. In the drawing, a thermoelectric power generation bodyis a cell configured so that a solidified redox reaction system (A) anda solidified redox (B) having a direct connection region with thesolidified redox reaction system (A) on its one side and contacting asulfide semiconductor on the other side sandwiches an electrode foroxidation, and the face of the sulfide semiconductor not contacting thesolidified redox (B) contacts a cathode. A voltage E₀ is applied betweenthe electrode for oxidation and the cathode by an auxiliary power sourcevia an adjusting paper resistance R₀ and a supplementary power circuit0. The output power can be taken out by connecting a load circuit 1 witha load resistance R1 between the cathode and anode.

[0079] i) The solidified redox reaction system (A) is given gaspermeability to make the transmission of oxygen easy and followingreactions are allowed to occur in region (X), (Y), and (Z):

[0080] In region (X); H₂O+1/20₂+2e⁻→20H⁻

[0081] In region (Y); 20H⁻→H₂O+1/20₂ ₊2e³¹

[0082] In region (Z); H₂O+1/20₂+2e⁻→20H⁻

[0083] RED→OX⁺+e⁻

[0084] ii) The solidified redox reaction system (B) is givennon-permeability of O² and resistant property to permeation of OH⁻, toprevent the transfer of these activated matter.

[0085] iii) By providing the direct connection range of the solidifiedredox reaction systems (A) and (B), the low potential generated in thereaction system (A) is transferred to the reaction system (B) tomaintain the potential of the reaction system (B) to a low level, bywhich the density of reduction type complex ion and that of oxidationtype complex ion are maintained in an appropriate relation.

[0086] iv) The electrons liberated at the cathode flows into the redoxreaction system (B) as diode current. The electrons have high potentialsand have the possibility of exerting the destructive reduction action tothe redox reaction system as follows:

Cu⁺(NH₃)₂ +e ⁻→Cu+2NH₃(Aq) E ⁰=−0.12V vs NHE

[0087] Therefore, it is required to reduce the reaction system (B) to acomplex ion species which is resistant to destruction. Here, theinventors paid attention to Ni²⁺(NH₃)₆. The destructive reductionreaction of this complex ion is well known.

Ni²⁺(NH₃)₆+2e ⁻→Ni+6NH₃(Aq) E ⁰=−0.49V vs NHE

[0088] This complex ion is far the more resistant to destruction thanCu⁺ (NH₃)₂. However, whether Ni²⁺(NH₃)₆ exhibits redox reaction behavioror not could not be found in literatures.

[0089] [Ni(CN)₄]³⁻˜[Ni(CN)₄]²⁻ is known in a redox reaction system whichNi ion forms, and this is the change of Ni←→Ni²⁺+e⁻.

[0090] On the assumption that a complex ion group with NH₃ also exhibitsredox reaction behavior, the inventors assumed as:

Ni⁺(NH₃)₆→Ni²⁺(NH₃)₆ +e ⁻ E ⁰=−0.2V vs NHE

[0091] v) The following reaction is known as redox reaction which doesnot suffer destructive reduction:

[Fe(CN)₆]³⁻ +e ⁻→[Fe(CN)₆]⁴⁻ E ⁰=−0.36V vs NHE

[0092] The destructive reduction reaction of this complex ion species is

[Fe(CN)₆]⁴⁻+2e ⁻→Fe+6CN⁻ E ⁰=−1.8V vs NHE

[0093] and this reaction does not occur by the electrons liberated at Fecathode. Therefore, the reaction system can be said to be superiorconcerning the two points mentioned above. However, [Fe(CN)₆]³⁻generates nascent oxygen when meeting with an alkali by the followingreaction and adversely affects against the sulfide semiconductor and Fecathode.

2[Fe(CN)₆]³⁻+2OH⁻→2[Fe(CN)₆]⁴⁻+H₂O+O

[0094] vi) In view of the circumstances mentioned heretofore, theinventors obtained a finding that it is suitable to make the redoxreaction system (B) non-permeable to gas and OH⁻ by using [Fe(CN)₆]⁴⁻ ascomplex ion and filling fine spaces in the layer with a binderconsisting of organic polymeric matter when solidifying the system to bemounted on the thermoelectric power generation body. Thus, the inventionas shown in FIG. 3 was completed. A concrete example will be describedlater as embodiment example 2.

[0095] Next, the inventors investigated concerning what the peculiaraction of activated carbon arises from and obtained further findings.The thermoelectric conversion according to the present invention ispossible by the interlocking of adjoining redox reaction system andsemiconductor as shown in FIG. 2. In FIG. 2, symbols denoted as follows:RED reduction type complex ion OX⁺ oxidation type complex ion (1)thermal excitation between bands (2) electron separation ψ_(B) redoxreaction potential ψ_(C) cathode reaction potential

[0096] The redox reaction system bears the role of electric conductionand generation of low reaction potential, the semiconductor bears therole of thermal excitation between bands and succeeding separation ofelectrons.

[0097] The inventors ascertained that the rate-determining factor is therate of redox reaction in the redox reaction system in which theregulating factor of flow rate of the electrons transferring frominterface A to interface C is the reaction rate in the redox reactionsystem and the thermal excitation rate between bands and diode electronflow rate in the semiconductor. With this being the situation, theinventors succeeded in generating a large electric current without usingactivated carbon by adding a direct electron conduction passage bydividing the roles such that the main role of the redox reaction systemis to generate low reaction potential and that of the direct electronconduction passage is the transfer of electrons. This relation is shownin the fourth embodiment example and the third comparison example.

[0098] Thus, it was clarified that it was due to the large contributionof the electric conductivity of the activated carbon that the powderedactivated carbon made the generation of the large electric currentpossible. Actually, tester probes were inserted in powdered activatedcarbon of Kanntou Chemicals Ltd. make used in experiments to measureresistance, and 0.8 kΩ was measured when the distance of the probes is 1cm.

[0099] In the case the role of reaction potential generation and theroll of electron transfer are divided as in the present invention, sincethe adsorbent of redox reaction liquid need not have electron transferability, any of general-purpose adsorbent such as activated carbon,charcoal, silica gel, molecular sieve, and burnt gypsum may be adopted,and further soccer ball-like carbon which is new material can be used aswell. It is permissible to select among them a material having thestrongest adsorbing ability for the complex ions composing the redoxsystem. Here, the adsorbing ability means adsorption density and fixingstrength.

[0100] As material for bearing the role of electron conduction,platinum, gold, graphite, etc. having high electrochemical stability aresuitable. The material should be allowed to coexist in the redoxreaction system in the form of flocculus, net, or chip. Aside from this,Cu₂S which is a p-type semiconductor may be used as electrode material.

[0101] The inventors investigated concerning the method for reducing theadverse effect of diode current. The diode current should be minimizedas mentioned before since it induces the destructive reduction of theredox reaction system. On the other hand, it is well known in a crystalsemiconductor that the diode current is reduced to a small value by pnjunction.

[0102] Based on this fact mentioned above, the inventors made an anisotype hetero junction body with p-type Cu₂S of sulfide semiconductor in astate of cluster of fine particles and n-type FeS, and attained thedesired result.

[0103] Specifically, Cu₂S is provided instead of the solidified redoxreaction system (B) in the thermoelectric power generation bodyconfigured as shown in FIG. 3. In this case, it is necessary to producethe state having non-permeability of gas and OH⁻ by adding a binderconsisting of organic macromolecular matter the same as in thesolidified redox reaction system (B).

[0104] The result of power generation by the thermoelectric powergeneration body of this type is shown in the third example.

[0105] The inventors also takes note of the fact that there are twosignificant meanings in removing the water solution of electrolyte fromthe cathode region.

[0106] In a thermoelectric power generation body configured in thefollowing form:

[0107] only that the lower reaction potential generating at interface(B) is connected with the higher reaction potential generating atinterface (C) by the medium of the semiconductor is necessary, and thatthe redox reaction system and the cathode form a chemical battery is notnecessary. On the contrary, the chemical battery is harmful and shouldbe eliminated.

[0108] It is useful for suppressing the re-elution of water solutionfrom the solidified redox reaction system as mentioned before and alsofor suppressing the advancing of chemical battery action as mentionedabove not to provide the room of the water solution of electrolyte inthe cathode region. However, if the cathode contact is entirely dry,reaction potential is not generated. By impregnating glycerol orglycerol with water added in region (C) instead of the water solution ofelectrolyte, continuous power generation has become possible.

[0109] The basic operation for realizing thermoelectric power generationthe inventors conceived and invented will be wholly summarizedhereinbelow.

[0110] The first operation is to allow the thermal excited electronsbetween bands in a semiconductor to gather to the region of cathodecontact of the conduction band, on the other hand, positive holes in thevalence band to gather to the region of anode contact. This action canbe realized by allowing the semiconductor to contain an appropriateelectric field in it.

[0111] The second operation is to allow a higher fermi level of cathoderegion than that of anode region by giving to the carriers gathering toboth planes of the semiconductor the energy or density or both of themfor the carriers to violate the equilibrium.

[0112] The first means for realizing this is the method in whichelectrochemical reaction is allowed to exist in either plane of thesemiconductor and the density of minor carrier on the plane is increasedto violate the equilibrium.

[0113] The second means is the method in which electrochemical reactionhaving lower reaction potential on the vacuum basis is allowed to existin the anode side, on the other hand that having higher reactionpotential on the vacuum basis is allowed to exist in the cathode side,and the potential difference of both reactions is applied to thesemiconductor as forward bias voltage. As to the power output, thesecond means is overwhelmingly superior.

[0114] The third operation is to select a large area sheet-likesemiconductor which is suitable for realizing the first and secondoperation and also suitable for mass production of the thermoelectricpower generation body. This can be realized by forming and hardeningwet, fine particles of sulfide semiconductor by use of appropriatebinder and carrier.

[0115] The fourth operation is to suppress the corrosion of cathodeinduced by the intrusion of reactive matter in the cathode range byallowing suitable adsorbent such as activated carbon to carry the watersolution of the reactive matter, thus solidifying the redox reactionsystem used as generating source of the lower reaction potentialnecessary for the anode side.

[0116] The fifth operation is not to allow the chemical battery reactionto proceed between the electrochemical reaction at anode side and thatat cathode side in the thermoelectric power generation body formed bythe second means of the second operation. It is important not to allowsubstantial absorption of electrons to occur in the redox reactionsystem, since, if the substantial adsorption of electrons occurs in theredox reaction system acting at the anode side, which induces theliberation reaction of electrons and allows the chemical batteryreaction to proceed. The auxiliary oxidation electrode provided in theredox reaction system works to achieve this. Further, it is alsoimportant that the range of anode and cathode are linked by ions and thetransfer of the ions is suppressed.

[0117] Thermoelectric power generation is possible when the first andsecond operation among the five operations are established at the sametime. However, the attainment of practicability requires theestablishment of the whole operations from the first to the fifth at thesame time.

[0118] By the way, the inventors cited in the first application,Japanese Unexamined Patent Publication 6-151978, mainly about the firstoperation and the means for realizing the operation, and concerning thesecond operation, the first means is mentioned only slightly.

[0119] The first operation and the means for realizing the operation arepublicly known, however, the idea of utilizing them for a thermoelectricpower generation body was a fresh one at the time and it is thought tobe meaningful that examples of devices realizing the second operationare disclosed in the application.

[0120] The inventors described extensively concerning the second meansof the second operation and the third operation in Japanese UnexaminedPatent Publication 8-306964. The inventor's understanding of the essenceof action was unripe at the time, although they had recognized rightlyconcerning the means for solving the problem. The present inventionopens the way to practical use of a thermoelectric power generation bodyby cultivating a better understanding on the essence of action in thesecond operation and adding the forth and fifth operations.

The First Example

[0121] The solidified redox reaction system 13 was formed by allowingthe saturated water solution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)_(2+n) (n=0, 1, 2)}to be adsorbed to a proper amount of activated carbon powder to be madeinto a state of coagulated powder without free liquid phase, adding asmall amount of burnt gypsum, a proper amount of crystal grains ofammonium chloride, and glycerol added with water to reduce thecoagulated powder to a slurry to be poured into a determined mold andhardened. A large number of pores was made to increase surface area inthe process of hardening.

[0122] FeS 14 was formed by adding S in the form of water solution of 15wt % of K₂S²⁻ to a determined amount of crystal grains of FeSO₄.7H₂O sothat the equivalence ratio of S²⁻/Fe²⁺ was 0.90 to cause raction. Asmall amount of ZnCl₂ powder was added to the obtained colloidalreaction product to fix the remaining free S²⁻ as ZnS.

[0123] The preparation of these sulfides was done in an atmospherewithout air or preferably in inert-gas atmosphere.

[0124] A proper amount of burnt gypsum was added as hardening agent tothe reaction product to reduce it to slurry. The slurry was carried onwater retaining papers of determined size, then determined numbers ofsheets of the papers were overlapped, pressed, and hardened.

[0125] The electric conduction type of the FeS prepared by this methodwas determined as n-type from the measurement of Seebeck effect. A smallamount of glycerol was allowed to permeate in the cathode range of FeS.The action area of the FeS layer provided on the device was consistently4 cm².

[0126] The cathode 15 was a thin plate of pure iron contacting FeS 14prepared by the method mentioned above in accordance with the determinedarrangement as shown in FIG. 1 showing the construction of the device.Then, the solidified redox reaction system 13 was brought into contactwith FeS 14, and the anode 11 of corrugated platinum thin plate wasbrought into contact with the redox system 13 using the anode holdingjig 12 so that part of the solidified redox system 13 was exposed to theatmosphere. Then they were tightened together from outside to completethe assemblage of the device.

[0127] The power generation performance (under operation temperature of40˜45° C.) of a device thus prepared is shown in Table 3, and slightcathode corrosion was observed. TABLE 3 Breakaway voltage 0.83 ˜ 0.86 VAttenuation after continuous generation Load resistance (Ω) Output (mW)for 5 Hrs. 330 1.5 No attenuation 170 2.7 No attenuation  45 3.9 Slightattenuation

The Second Example

[0128] The solidified redox reaction system 13 was formed according toFIG. 3 by coupling reaction system (A) of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)₄} andreaction system (B) of Ni²⁺(NH₃)₆. At first, reaction system (B) wasprepared by adding a determined amount of activated carbon powder to thewater solution of Ni²⁺(NH₃)₆ and mixing sufficiently, then adding adetermined amount of burnt gypsum and water and mixing sufficiently.

[0129] Then, after adding a bond for wood working and mixingsufficiently, the obtained slurry-like mixture was poured into adetermined mold and hardened. A bond for wood working or the like wasfilled in the gap developed between the mold and the mixture due to theshrinkage of the hardened mixture. After completion of this process, thesupplementary platinum electrode for oxidation was installed and theframe for reaction system (A) was fitted.

[0130] Then, a determined amount of ammonium chloride was added to thesaturated water solution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)₄}, a proper amount ofactivated carbon powder was added and mixed sufficiently, after that adetermined amount of burnt gypsum and water was added and mixedsufficiently to reduce the mixture to a slurry state. The slurry waspoured into a mold prepared beforehand and hardened.

[0131] Here the area of the supplementary platinum electrode should besmaller than that of the electric conduction plane of the redox reactionsystem to secure the direct connection region of reaction system (A)with reaction system (B).

[0132] Next, FeS 14 was formed by adding S²⁻ in the form of watersolution of 15 wt % of K₂S to a determined amount of crystal grains ofFeSO₄.7H₂O so that the equivalence ratio of S²⁻/Fe²⁺ is 0.90 to causereaction, and adding a small amount of ZnCl₂ powder to the colloidalreaction product obtained to react with the remaining S²⁻. Thepreparation of these sulfides was done in an atmosphere without air orpreferably in inert-gas atmosphere.

[0133] Then, after a determined amount of burnt gypsum was added andmixed sufficiently, the reaction product was carried on water retainingpapers of determined size wetted with ethanol anhydride, requirednumbers of sheets of the papers were overlapped, pressed, and hardened.

[0134] The cathode 15 made of a thin plate of pure iron and the anode 11made of a corrugated thin plate of platinum were used, the redoxreaction system 13 respectively by using the anode holding jig 12 suchthat part of the redox reaction system 13 was exposed to the atmosphere,and the assemblage of the device was completed by tightening them fromoutside.

[0135] The power generation performance under operation temperature of37˜41° C. of the device thus prepared is shown in Table 4. No cathodecorrosion was observed. TABLE 4 Breakaway voltage (V) 0.72 ˜ 0.75Current (mA); Load resistance: 85 Ω 5.3 Power (mW); Load resistance: 85Ω 2.4 Quantity of electricity (Coulomb) 490 Supplementary current (mA)0.25 Attenuation after continuous No attenuation generation for 25 Hrs.

The Third Example

[0136] The thermoelectric power generation body was composed as shown inFIG. 4.

[0137] At first, Cu₂S layer was formed. S²⁻ in the form of watersolution of 15 wt % of K₂S was added to a determined amount of CuClpowder for reaction so that the equivalence ratio of S²⁻/2Cu⁺ was 1.0,filter paper was pushed against the reaction product to dehydrate. Thepreparation of these sulfides was done in an atmosphere without air orpreferably in inert-gas atmosphere.

[0138] A determined amount of burnt gypsum was added to the obtainedcake and mixed, further a determined amount of a bond for wood workingwas added and mixed sufficiently. The obtained viscous liquid was filledin a determined mold and hardened. As the hardened substance shrank inthe mold to develop a gap between them, a bond for wood wprking wasfilled in the gap.

[0139] The supplementary platinum electrode for oxidation was installedto the Cu₂S layer and the frame for the redox reaction system 13 wasfitted. Here the area of the supplementary platinum electrode should besmaller than that of the electric conduction plane of the Cu₂S layer tosecure the direct connection region of the redox reaction system withCu₂S.

[0140] The redox reaction system 13 of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)₄} was formedby the same process as in the second example.

[0141] FeS 14 was formed also by the same process as in the secondexample. The cathode 15 was installed, the anode 11 was attached by themedium of the holding jig 12 so that part of the redox reaction system13 was exposed to the atmosphere, and finally they were tightened fromoutward to complete assemblage.

[0142] The power generation performance (under operation temperature of37˜41° C.) of the device thus prepared is shown in Table 5. No cathodecorrosion was observed. TABLE 5 Breakaway voltage (V) 0.78 ˜ 0.80Current (mA); Load resistance: 45 Ω 9.2 Power (mW); Load resistance: 45Ω 3.9 Quantity of electricity (Coulomb) 460 Supplementary current (mA)0.33 Attenuation after continuous No attenuation generation for 15 Hrs.

The Fourth Example

[0143] The solidified redox reaction system 23 was formed by allowingthe concentrated water solution of Ni²+(NH₃)₆ to be adsorbed to a properamount of charcoal powder to be made into a state of coagulated powderwithout free liquid phase, adding and mixing a large amount of graphitechips(about 3 mm×3 mm×0.38 mmt), and filling the mixture in a determinedmold.

[0144] FeS 24 was formed as in the first example.

[0145] A thin plate of pure iron and a thin corrugated plate of platinumwas used as the cathode 25 and anode 21 respectively. Each component wasarranged and brought into contact with other element in accordance withFIG. 1 showing the construction of the device and tightened from outwardto complete the assemblage of the device.

[0146] The power generation performance (under operation temperature of40˜45° C.) of the device thus prepared is shown in Table 6. TABLE 6Breakaway voltage 0.47 ˜ 0.50 V Attenuation Load after continuousresistance (Ω) Output (mW) generation for 2 Hrs. 25 0.60 Slightattenuation

The First Comparative Example

[0147] The saturated water solution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)_(2+n)(n=0,1, 2)} was used as the redox reaction system 33. It was poured into theliquid room of the liquid phase redox reaction system of the deviceconfigured as shown in FIG. 4 with its upper part open to theatmosphere.

[0148] FeS 34 was formed by adding S²⁻ in the form of water solution of15 wt % of K₂S to a determined amount of crystal grains of FeSO₄.7H₂O sothat the equivalence ratio of S²⁻/Fe²⁺ is 0.90 to cause reaction. Asmall amount of ZnCl₂ powder was added to the obtained colloidalreaction product to fix the remaining free S²⁻ as ZnS. The preparationof these sulfides was done in an atmosphere without air or preferably ininert-gas atmosphere. A bond for wood working of 1.2 times in volume wasadded to the obtained reaction product and mixed. The obtained viscousslurry was carried on water retaining paper of determined size, requirednumbers of sheets of the paper were overlapped, pressed, and hardened.The hardened solid body was installed in a chamber made of rubber plate,and the periphery of the solid body was glued to the chamber with a bondfor wood working so that no gaps were remained. The reason a bond forwood working was used is to prevent the permeation of reaction liquid byfilling vacant spaces and to allow the FeS layer to be moist to theminimum extent required.

[0149] A thin wire of pure iron wound in a spiral coil was used ascathode 35 which was immersed in glycerol in the cathode room of thedevice constructed as shown in FIG. 5. By this the redox reaction liquidis difficult to transfer to the cathode room.

[0150] A thin plate of graphite was used as anode 31, and the device wasassembled by the same method as in the first example as shown in FIG. 5.

[0151] The power generation performance (under operation temperature of40˜42° C.) of the device is shown in Table 7. However, the corrosion ofcathode occurred considerably when the generated quantity of electricitywas 750 coulombs. However, the amount of corrosion was far smallcompared with that estimated in correspondence with the generatedquantity of electricity. TABLE 7 Breakaway voltage 0.63 V AttenuationLoad after continuous resistance (Ω) Output (mW) generation for 5 Hrs.68 1.7 Almost no attenuation 50 1.7 Slight attenuation

The Second Comparative Example

[0152] The different point from the first example was only that thesolidified redox reaction system was shut off from the atmosphere, theconditions other than that were the same as in the first example. Theconstruction of the device is shown in FIG. 6. The power generationperformance (under operation temperature of 40˜45° C.) of the device isshown in Table 8. TABLE 8 Breakaway voltage 0.83 V Attenuation Loadafter continuous resistance (Ω) Output (mW) generation for 5 Hrs. 3301.4 Considerable attenuation

The Third Comparative Example

[0153] A concentrated water solution of Ni²⁺(NH₃)₆ was used as originalliquid for the solidified redox reaction system 23. The solution wasadsorbed to a proper amount of charcoal powder to reduce the solution toa state of coagulated powder without free liquid phase. Then a properamount of burnt gypsum and water was added to reduce the coagulatedpowder to slurry. The slurry was poured into a determined mold andhardened.

[0154] FeS 24 was formed by the same method as in the first example.

[0155] A thin plate of pure iron and a thin plate of platinum was usedas cathode 25 and anode 21 respectively. Each constituent element wasarranged and contacted as shown in FIG. 6, and tightened from outside tocomplete the assemblage of the device. The power generation performance(under operation temperature of 44˜47° C.) of the device thus preparedis shown in Table 9. TABLE 9 Breakaway voltage 0.74 V Attenuation Loadafter continuous resistance (Ω) Output (mW) generation for 2 Hrs. 250.02 No attenuation

Industrial Applicability

[0156] As cited above, according to the present invention, theconversion of thermal energy to electric power is possible with highthermal efficiency.

[0157] The thermoelectric power generation body according to the presentinvention uses the electric potential of electrochemical reaction assource of function and is of compact construction with less wear andeasy maintenance.

[0158] Moreover, semiconductors suitable for mass production are used,which is beneficial to general purpose use of the thermoelectric powergeneration body of the present invention.

1. A thermoelectric power generation body configured so as to be able toconvert heat to electric power by allowing an electrochemical reactionhaving lower reaction potential on the vacuum basis to exist in theregion of one plane of a solid layer which is made of fine particles ofsulfide semiconductor hardened in the shape of thin plate in the statecontaining water and by allowing an electrochemical reaction havinghigher reaction potential on the vacuum basis to exist in the region ofthe other plane thereof, wherein the reaction system having lowerreaction potential is a redox reaction system solidified by allowing thewater solution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)_(2+n)(n=0, 1, 2)} or Ni²⁺(NH₃)₆to be adsorbed to an adsorbent having adsorptive and electron conductiveproperties.
 2. A thermoelectric power generation body according to claim1, wherein the solidified redox reaction system is enabled to operateunder the presence of the atmosphere by allowing the adsorbent havingadsorptive and electron conductive properties to adsorb the watersolution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)_(2+n)(n=0, 1, 2) } or Ni²⁺(NH₃)₆,further adding ammonium salt, burnt gypsum, or hydrophilicmacromolecular matter necessary for hardening, and taking a measure suchas making pores for increasing the surface area in the process ofsolidification.
 3. A thermoelectric power generation body according toclaim 1, wherein the redox reaction system exists between the firstregion contacting the atmosphere and the sulfide semiconductor, thefirst region allowing the continuous generation of the potential of thefollowing reaction (1) without accompanying the substantial absorptionof electrons by the equilibration of the reaction (1) toward the rightand left; the redox reaction occurs steadily with the potential of thereaction (1) given; and the second region which prevents the transfer ofO₂ and OH⁻ existing in the first region toward the cathode is connectedwith the first region, thereby the induction of electron liberationreaction at the cathode due to the reaction (1) acting in the redoxreaction system and bearing the steadiness of the redox reaction isprevented. H₂O+1/2O₂+2e ⁻←→2OH⁻  (1)
 4. A thermoelectric powergeneration body according to claim 3, wherein an electrode for oxidationconnected to an auxiliary electric power source is provided in the redoxreaction system, thereby the reaction (1) is allowed to proceed towardthe left.
 5. A thermoelectric power generation body according to claim3, wherein the power generation body has the second region consisting ofa redox reaction system solidified into the state not having gaspermeability, the reaction system being solidified by adding a binder toan adsorbent adsorbed the water solution of {Cu⁺(NH₃)₂˜Cu²⁺(NH₃)₄} orNi²⁺(NH₃)₆, the binder consisting of burnt gypsum and hydrophilicmacromolecular matter and having a function to fill a thin gap, theadsorbent having both adsorptivity and electric conductivity.
 6. Athermoelectric power generation body according to claim 3, wherein thesolidified redox reaction system performs redox reaction which takespart in the generation of lower reaction potential on the vacuum basisand electric conduction by the reaction on the interface with thesemiconductor, and an electron conduction passage which takes part inthe transfer of electrons in the layer is provided.
 7. A thermoelectricpower generation body according to claim 4, wherein, in a role sharingtype solidified reaction system, the adsorbent of the water solution ofcomplex ions is activated carbon, charcoal, silica gel, burnt gypsum,molecular sieve, or soccer ball-like carbon, and the electron conductionmaterial is platinum, gold, graphite, or Cu₂S.
 8. A thermoelectric powergeneration body according to claim 1, wherein the sulfide semiconductoris prepared by the method in which the semiconductor material isselected among coprecipitated deposit of Cu₂S, FeS, Fe₂S₃, NiS, FeS.NiS, FeS. ZnS, chloride or sulfate of constituent cation is reacted withsulfur ion in the water solution of 10˜20 wt % of potassium sulfide orsodium sulfide so that the equivalence ratio of sulfur ion/cation is0.85˜1.1, zinc chloride powder is added to react with the colloidalproduct obtained, then the slurry is added with burnt gypsum orhydrophilic macromolecular matter as hardening agent to be hardened. 9.A thermoelectric power generation body according to claim 8, wherein thesulfide semiconductor is prepared by the method in which thesemiconductor material is selected among coprecipitated deposit of Cu₂S,FeS, Fe₂S₃, NiS, FeS. NiS, FeS. ZnS, chloride or sulfate of constituentcation is reacted with sulfur ion in the water solution of 10˜20 wt % ofpotassium sulfide or sodium sulfide so that the equivalence ratio ofsulfur ion/cation is 0.85˜1.1, zinc chloride powder is added to reactwith the colloidal product obtained, then the slurry added with burntgypsum or hydrophilic macromolecular matter as hardening agent iscarried on water retaining papers, and a plurality of the sheets of thepapers are overlapped, pressed to be hardened and shaped.
 10. Athermoelectric power generation body according to claim 1 or 8, whereinthe semiconductor layer consists of single n-type or single p-typesulfide semiconductor.
 11. A thermoelectric power generation bodyaccording to claim 1 or 8, wherein the semiconductor layer is of anisotype hetero junction of a p-type sulfide semiconductor located in theanode side and a n-type sulfide semiconductor located in the cathodeside.
 12. A thermoelectric power generation body according to claim 1,wherein the reaction for generating higher reaction potential on thevacuum basis at the plane opposite to that which the solidified reactionsystem contacts is an equilibrating reaction formed by allowing materialhaving chemical reaction activity such as iron, nickel, copper, brass.used as cathode to contact the sulfide semiconductor in a quasi-drystate or in a solution other than water solution of glycerol, etc.having relatively high permittivity alone or in a state in whichglycerol, etc. and water added by a small amount coexist.